Packing



Feb. 17, 1931. w, STEVENS 1,792,875

PACKING Filed March 17, 1925 I N VEN TOR Edward W Sfevens BY Al'sATTORNEY Patented Feb. 17, 1931 UNITED STATES PATENT OFFICE- nnwann w.srnvnns, or person, MICHIGAN, nssreno'n 'ro cmcaeo immune 'roor.comrnnv, or new YORK, 1v. Y., A conronnrron or NEW- messyApplication-filed new; 11.1925. Serial 80.18995.

The present invention relates to packings generally as for reciprocatingrods with particular reference to fluid pressure tools such as pneumaticsand rammers'.

In order that a pneumatic sand rammer may operate efiiciently it isessential that the packing for the rammer rod maintain a ti ht seal forthe outer end of the piston cham er since motive fluid is admittedthereto at the end of each forward movement of the piston to effect itsreturn stroke. The usual practice has been to have the packing glandsmake a loose fit in the forward end of the cylinder with the packingcompressed therebetween and with the cylinder bore serving as a wall forthe packing. Not only is this loose fitting not conducive to a tightsealing of the iston chamber but it also leaves the piston co to exert aforce against the packin at every tends to, estroy the packing.

Among the objectsvof the invention are to avoid relative movement of thepacking mem bers which results in the destruction of the seal and of thepacking material, to reduce the amount of packing material required witha reduction in the pressure necessary to maintain the seal, to providefor manual adjustment of the packing without the use of tools, tofacilitate the handling and inserting of, new packings, to provide anewform of mold ed packing and protective container therefor. and ingeneral to improve prior structure in the interests of more efficientand satisfactory service.

In order to illustrate the invention and the manner of its use oneconcrete embodiment thereof is shown in the accompanying draw ings inwhich: v l Fig. 1 is a longitudinal sectional view through the forwardend of the cylinder of a pneumatic sand rammer; I

Fig. 2 is a right end elevation of the part shown in Fig. 1; I 1

Fig. 3 is a view similar to Fig. 1 on a reduced scale showing the mannerof insert-" in a new packing, and

iig. 4 is aperspective view of the molded packing in its container.

The embodiment of the invention chosen for the purpose of illustrationis shown in I the drawings as sealing the forwardend of the pistonchamber of a rammer comprising the cy inder or barrel 5 in which piston6 reciprocates, the latter having attached thereto or integral therewitha stem'fia which projects beyond the-cylnder 5 and carries the butt orpein (not shown). The motive fluidadmitted to the front end of thepiston chamber through passage 7 to drive piston 6 on its backstroke 1ssealed against escape through the forward open end of the cyhnder by thefollowing construction. A packin gland member 8 in the form of a hollowcylinder or sleeve is rigidly secured within the open end of thecylneumatic sandinder as shown. One method of rigidly se- I curingmember 8 in the cylinder is to provide'the latter'with internalscrewthreads 5a and: the member with external screw threads 8a. Oppositeslots as'8b permit the use of aspanner wrench for inserting member 8aand a shoulder 80 cooperating with a similar shoulder within cylinder 5serves as a stop. The cylinder bore 9 of member 8 receives stem 6a witha slidin fit and serves as a bearing for'thelatter. videdwith a counterbore 9a in which packing material 10 is seated'surrounding stem (iaand asecond gland member 11 in the form ofa cylinder sleevedover stem6a-makes a close sliding fit with counterbore 9a and telescopes withinmember 8 toplace packing 10 under compression. Member 11 is ofsubstantiallength as indicated and projects beyond cylinder 5. A glandnut 12 having a head 12a with a bore 126 loosely receiving stem 6a isprovided with a cylindrical extension 12c arranged loosely to telescopeover the projecting portion of member 11 and is ember 8 is pro- 1exteriorly threaded for engagement with the interior threads 5a ofcylinder 5. Head 12a is formed with a rim extending beyond cylinderportion 120 and interposed between this rim and the end of the cylinder5 and surrounding projection 120 is a coiled spring 13 whose ends 13aand 136 are removably seated in sockets 5b and 12d respectively incylinder 5 and nut head 12a to hold the manually adjustable nut 12 inadjusted position.

0 shown the mol ed packing in its container as a unit is sleeved overthe piston stem 6a until the container 14 abuts the outer end of member8. Gland member 11 is then sleeved over the stem 6a and is telescope'dwithin the container 14 forcing the molded packing 10 into thecounterbore 9a of gland member 8, the member 11 being forced throughpacking 10 and into telescopic engagement with member 8 until the partsreach the position shown in Fig. 1, t e packing then being seated in itsrecess. The container or envelope 14 is now removed from the stem 6a andthe gland nut '12 with its locking spring is a plied and set up to putpacking 10 under tlib desired compression. The tool is then ready foruse.

From the above it will be apparent that the rigid securing of glandmember 8 within the cylinder end prevents relative movement of the partsand provides a good bearing for the stem 6a, that the packing materialis contained wholly within the gland member 8 and protected from wearthrough 'relative movement of the adjacent parts, that the other glandmember 11 telescoping within member 8' and closely fitting the sameprovides additional bearin surface for stem 6a and closely confines t epacking material within rigid walls, that by this gland constructiononly a small amount of packing material and a relative low pressure ofthe same are required to seal the cylinder, that the telescopingengagement of member 11 and gland nut 12 serve as an additional supportfor the latter, that the low pressure required on packing 10 permitsmanual adjustment of nut 12, tains the nut 12 in its adjusted position.

While but one embodiment of the invention has been herein shown anddescribed it is to be understood that the invention is not limited tothe specific details thereof but covers all changes, modifications andadaptations within the scope of the appended claim.

The packing herein disclosed is claimed per se and as to the method ofapplyi the same in my copending application, erial No.

95,842, filed March 19th, 1926, as a division of this application.

I claim as my invention:

In a fluid pressure tool having a cylinder with an open end and a pistonreciprocable in the cylinder with a stem projecting therefrom, thecylinder having a long counterbore threaded substantially throughout itslength 7 and that the locking spring '13 re- Y meaaaa and forming aninternal shoulder, packing means for said piston stem comprising anelongate gland member sleeved over said stem and threaded into saidcounterbore to provide a rigid bearing for said stem, said member havinga shoulder to engage the internal shoulder of said cylinder, packingmaterial surrounding said stem within said member, a second gland membersleeved over said stem and telescoping within said first member with asliding fit, said second member being of substantial length andprojecting well beyond said cylinder, a nut sleeved over said stem andhaving a cylindrical extension telescoping over the projecting portionof said second gland member, said extension being exteriorly threaded toscrew into said counterbore of said cylinder in spaced relation to saidfirst gland member, said gland members and nut cooperating to permittightening of said packing material y the operator of the tool bygrasping the nut with his hand and turning Signed by me at Detroit,

12th day of March, 1925.

EDWARD W. STEVENS.

it. Michigan, this

